This is the end of the preview. Sign up
to
access the rest of the document.

Unformatted text preview: y i- y i ) 2 ] ( n-p ) Weighted Least Square Recall: Y i = + 1 x i + i i , i w-1 / 2 i r i = y i-( + 1 x i ) behave like i i r 2 i behave like 2 2 i 2 i r 2 i 2 i behave like 2 2 i Weighted Least Square Remark 1: Use WLS when the unequal variance is only problem. (heteroscedasticity: different variance) Remark 2: Give larger weight to the point with smaller variance As a result, one gets better efciency in and better power is testing. Remark3: Diagnostic plot should be performed on the weighted residual, w 1 / 2 i r i ....
View Full
Document